This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Prevalence and Incidence of Articular Symptoms and Signs Related to Psoriatic Arthritis in Patients With Psoriasis Severe or Moderate With Adalimumab Treatment (NCT01316224), a registered phase not stated study. The primary outcome is Percentage of Participants Who Developed Psoriatic Arthritis (PsA).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01316224 |
| Phase | Phase not stated |
| Condition | Psoriasis, Psoriatic Arthritis |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 52 |
| Arms in the primary outcome | n/a |
| Lead sponsor | AbbVie (prior sponsor, Abbott) |
| Results posted | Yes |
2. Clinical Question
Population
Participants with moderate or severe plaque psoriasis. The record reports an enrollment of 52 and describes the study population as being in Colombia. The primary outcome population is narrower: participants who completed rheumatologist visits 3 and 4 and for whom information was available.
Intervention
Adalimumab treatment. The record describes participants with moderate or severe plaque psoriasis receiving adalimumab; it does not report a separate untreated or alternative-treatment group.
Comparator
No like-for-like control comparison is described. Allocation is not stated, and the record flags that this is not a randomized comparison. The treatment group therefore cannot be interpreted as one arm of a randomized treatment contrast.
Primary question
What percentage of the eligible participants developed psoriatic arthritis, based on a rheumatologist’s diagnosis or specified joint and CASPAR criteria, at baseline and the planned follow-up visits? Although the registry names this outcome and its measurement times, its numerical results are not reported in the registry record.
The study’s stated purpose was to describe the profile of participants with moderate or severe plaque psoriasis in Colombia and to evaluate adalimumab efficacy and safety. The primary outcome focuses on whether participants met a definition of PsA, rather than on a randomized comparison of treatments. This makes the registry’s outcome definition and the makeup of the assessed population central to interpretation. The record also lists secondary measures related to psoriasis severity, joint findings, comorbidities, and quality of life, but their numerical results are not reported in the registry record.
3. Trial Design
NCT01316224 is a completed study titled “Prevalence and Incidence of Articular Symptoms and Signs Related to Psoriatic Arthritis in Patients With Psoriasis Severe or Moderate With Adalimumab Treatment.” The record gives a start date of 2011-04 and a primary completion date of 2014-04. AbbVie is listed as sponsor, with Abbott identified as the prior sponsor.
The enrollment is 52. The described group consists of participants with moderate or severe plaque psoriasis treated with adalimumab. Allocation is not stated, and the registry specifically indicates that this was not a randomized comparison and that the arms should not be treated as a like-for-like control comparison. The record does not describe a separate comparator group in the arm description. As a result, the design information does not support a randomized estimate of the effect of adalimumab relative to another treatment or to no treatment.
The primary outcome is the percentage of participants who developed PsA. It is assessed at baseline, visit 3 (month 6), and visit 4 (month 12). The primary outcome population is defined by completion of visits 3 and 4 to the rheumatologist and availability of information. The number of participants meeting that population definition is not reported in the registry record.
Listed secondary outcomes include time to first occurrence of PsA signs or symptoms; change in PASI, quality of life, and CASPAR score; PsA development among participants with comorbidities; CASPAR scores at rheumatologist visits; swollen and tender joint counts; and joint symptoms. The record lists 12 outcome measures, but numerical results for these outcomes are not reported in the registry record. Further detail on eligibility criteria, visit schedules beyond those named, treatment duration, and the statistical plan is not reported in the registry record.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Overall Study
| Stage | Moderate or Severe Psoriasis |
|---|---|
| STARTED | 52 |
| Completed Visit 1 to Dermatologist | 52 |
| Completed Visit 1 to Rheumatologist | 49 |
| Completed Visit 2 to Dermatologist | 51 |
| Completed Visit 3 to Dermatologist | 48 |
| Completed Visit 3 to Rheumatologist | 39 |
| Completed Visit 4 to Dermatologist | 42 |
| Completed Visit 4 to Rheumatologist | 28 |
| COMPLETED | 42 |
| NOT COMPLETED | 10 |
Reasons for not completing this period:
| Reason | Moderate or Severe Psoriasis |
|---|---|
| Protocol Violation | 3 |
| Adverse Event | 3 |
| Lack of Efficacy | 1 |
| Withdrawal by Subject | 1 |
| Adverse Event With Treatment Failure | 1 |
| Other | 1 |
Analysis population for the primary outcome, as defined in the registry: Participants who completed the visits (visit 3 and visit 4) to the rheumatologist and for whom information was available.
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
| Characteristic | Unit | Moderate or Severe Psoriasis |
|---|---|---|
| Participants analysed | 52 | |
| Age, Continuous | Years | 48.85 (SD 14.66) |
| Sex: Female, Male: Female | Participants | 21 |
| Sex: Female, Male: Male | Participants | 31 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 |
| Race (NIH/OMB): Asian | Participants | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 |
| Race (NIH/OMB): White | Participants | 18 |
| Race (NIH/OMB): More than one race | Participants | 34 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Region of Enrollment: Colombia | Participants | 52 |
| Weight | kg | 78.70 (SD 14.70) |
| Body Mass Index (BMI) | kg/m^2 | 28.83 (SD 5.06) |
| C-Reactive Protein (CRP) (N=10) | mg/dl | 1.39 (SD 1.63) |
| Study Specific Characteristic: Participants Who Smoke | Participants | 21 |
| Study Specific Characteristic: Positive History of Comorbidities | Participants | 28 |
| Study Specific Characteristic: Presence of Metabolic Syndrome | Participants | 8 |
| Study Specific Characteristic: Presence of Hypertension | Participants | 15 |
| Study Specific Characteristic: Presence of Family History of PsA (N=49) | Participants | 11 |
| Study Specific Characteristic: Prior Methotrexate Use | Participants | 36 |
| Study Specific Characteristic: Current Methotrexate Use | Participants | 11 |
| Study Specific Characteristic: Prior Biologic Therapy | Participants | 14 |
6. Primary Endpoint
The registry lists the primary outcome as Percentage of Participants Who Developed Psoriatic Arthritis (PsA), measured over At Baseline, Visit 3 (month 6) and Visit 4 (month 12).
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | Percentage of participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the percentage of participants who developed psoriatic arthritis. The registry defines PsA as present when a rheumatologist makes the diagnosis, when a participant has inflamed joints greater than zero and a CASPAR score at least 3, or when either of those definitions is met. This combines a clinician’s assessment with specified joint and classification criteria. The measure is reported as a percentage rather than as a continuous measure of symptom severity.
The specified assessment times are baseline, visit 3 (month 6), and visit 4 (month 12). The primary outcome population consists of participants who completed the rheumatologist visits at visits 3 and 4 and for whom information was available. This eligibility condition matters: the outcome is not necessarily a percentage among everyone enrolled, and the registry does not report the size of the assessed population or the number meeting the PsA definition.
In general, a percentage endpoint gives a direct description of how common a defined event is within the population assessed. Repeated measurements can describe how that percentage varies across the recorded visits, but they do not by themselves establish why it changed. In this case, the endpoint could describe PsA occurrence among the assessed participants, but the numerical outcome is not reported in the registry record. The registry also does not report a confidence interval or other measure of precision for the primary percentage.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a clinically defined primary outcome and specifies when it was intended to be assessed, but it does not report the outcome values. There is therefore no posted percentage of participants meeting the PsA definition at baseline, visit 3, or visit 4 to interpret. No direction or magnitude of change across visits can be described from the record, and no estimate of precision is reported. The absence of numerical outcome results is not evidence that the event did or did not occur.
The stated enrollment is 52, but that number should not be mistaken for the denominator of the primary endpoint. The endpoint’s population definition requires completion of visits 3 and 4 and available information. The count meeting those conditions is not reported in the registry record. Without the relevant denominator and event count, the primary percentage cannot be independently checked or interpreted in terms of how much information supports it.
The study description identifies adalimumab-treated participants but does not give a randomized control comparison. The registry also says allocation is not stated and cautions against treating arms as like-for-like controls. Accordingly, even if a before-and-after pattern had been reported, it would describe the observed group over time; it would not, on its own, separate treatment effects from other explanations for change. Since the primary numerical results are absent, even that descriptive pattern cannot be assessed.
The record lists secondary outcomes covering PsA timing and classification, psoriasis severity, joint symptoms and counts, comorbidities, and quality of life. Their names indicate the breadth of the planned description, but do not reveal what was observed. Numerical results, uncertainty estimates, and inferential tests for those outcomes are not reported in the registry record. The record also lists no analysis records, so there are no posted analysis estimates to compare with the outcome definitions.
Serious and other adverse-event counts are listed separately from the primary efficacy outcome. These safety entries describe events recorded in the treatment group; they do not fill the gap in the PsA outcome results or provide a comparative safety estimate. The serious-event terms and percentages are also not a substitute for a complete account of event severity, timing, or relationship to treatment. Those details are not reported in the registry record.
Overall, the record supports a description of the study question, treatment group, endpoint definition, and certain safety counts. It does not support a quantitative conclusion about the frequency of PsA in the primary outcome population, change over time, or a causal treatment effect. Any interpretation should keep those distinctions clear.
9. Statistical Methods Explained
The primary outcome is a binary event summarized as a percentage: a participant either meets the registry’s PsA definition at an assessment or does not. In general, a percentage is calculated using the number of participants meeting the event definition relative to the eligible denominator. Here, the registry specifies the relevant population as participants who completed visits 3 and 4 to the rheumatologist and had information available. Because the event count and assessed denominator are not reported in the registry record, the percentage cannot be reconstructed from the record.
What does the case definition capture?
The registry allows PsA to be identified through a rheumatologist’s diagnosis or through the combination of inflamed joints greater than zero and a CASPAR score at least 3. It also states that meeting either of the first two definitions qualifies. Using more than one route to define an event can capture cases identified clinically as well as cases meeting specified examination and classification criteria. In general, such a composite definition can be broader than relying on one criterion alone. Interpretation depends on applying the definition consistently across participants and visits; the record does not report additional adjudication procedures.
The primary measure is a percentage at baseline and later visits, rather than a model-based estimate of time to event. The record separately lists mean time to first occurrence of PsA signs or symptoms as a secondary outcome. In general, time-to-event methods account for both when an event occurs and whether observation ends before the event is seen. The registry does not report numerical time-to-event results, the method used to analyze them, or details about censoring.
How should uncertainty be understood?
In general, a confidence interval expresses the range of estimates compatible with the observed data under a statistical procedure. Its width reflects precision: estimates based on less information tend to be less precise, while more information can narrow the interval. A point estimate alone does not communicate this uncertainty. No confidence interval for the primary percentage is reported in the registry record, and no event count or eligible denominator is given from which to assess its precision.
Repeated percentages at different visits can be useful descriptively, but the observations come from participants followed over time, not necessarily from independent groups. General statistical analysis of repeated measurements should account for that within-participant relationship when making inferential claims. The registry record does not report whether a repeated-measures method was used, how missing visits were handled, or whether estimates were adjusted for other characteristics.
What does the design allow?
In general, random allocation helps balance measured and unmeasured characteristics between treatment groups, supporting a causal comparison when the study is conducted and analyzed appropriately. This record does not describe a randomized comparison; allocation is not stated, and the registry warns that arms are not like-for-like controls. Thus the study’s described treatment group can support a descriptive account of outcomes in that group, but the record does not establish a randomized contrast between adalimumab and another condition. The statistical plan and any adjustment strategy are not reported in the registry record.
The record includes a sample-size planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. Such illustrations are planning calculations, not observed power and not a report of how the study was designed. In general, a planning calculation asks how much information might be needed to detect a chosen effect under stated assumptions. Its result depends on the assumed effect and analytic conditions. The registry does not report the study’s own sample-size justification or statistical design plan, so the illustration should not be read as evidence that the study was prospectively designed around those assumptions.
Over-dispersion is a general concern when observed variation in count or binary data exceeds what a simple statistical model expects. If present, a model that assumes less variation can understate uncertainty and make results appear more precise than warranted. No model, dispersion assessment, or inferential analysis is reported for the primary outcome in this record, so there is no basis for claiming that over-dispersion was assessed or relevant to a particular reported estimate.
The record lists 12 outcome measures, spanning several types of data. In general, different outcome types may call for different summaries and methods: percentages for binary outcomes, means for continuous measures, and time-to-event methods for event timing. The outcome names alone do not establish which statistical methods were used. The registry record does not report the analysis procedures, confidence intervals, hypothesis tests, or any adjustments for multiple comparisons.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 12 outcome measures, including the primary percentage and secondary measures of event timing, psoriasis severity, joint findings, classification scores, comorbidities, and quality of life. When many outcomes or repeated assessments are considered, general statistical practice recognizes that the chance of at least one apparently notable result can increase if many tests are conducted. A prespecified hierarchy or multiplicity adjustment can address some of this concern. The statistical plan, any outcome hierarchy, and any multiplicity procedure are not reported in the registry record. Numerical tests are not reported either, so the impact of multiplicity on specific findings cannot be assessed.
The primary population is restricted to participants who completed visits 3 and 4 to the rheumatologist and had information available. The number meeting this requirement, the number with missing information, and the reasons for missingness are not reported in the registry record. These omissions matter because the analyzed subset may differ from all enrolled participants. In general, complete-case summaries can be affected if participants with missing assessments differ systematically from participants with observed assessments.
The registry does not report whether missing data were imputed, whether participants were analyzed according to a particular analysis population, or whether sensitivity analyses were performed. It also does not report an intention-to-treat definition or a per-protocol definition. The appropriate interpretation is therefore limited to the stated outcome population; assumptions about how missing observations were handled cannot be filled in from the record.
The record lists no analysis records. This means there are no registry-posted numerical analyses to evaluate for multiplicity, missing-data handling, or consistency with a statistical plan. Interim analyses and stopping rules are not reported in the registry record.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Moderate or Severe Psoriasis | 16 | 52 | 30.8% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Moderate or Severe Psoriasis | 5 of 52 |
Most frequent serious adverse event terms
| Event term | Organ system | Moderate or Severe Psoriasis |
|---|---|---|
| Neck pain | Musculoskeletal and connective tissue disorders | 2 of 52 |
| Psoriatic arthropathy | Musculoskeletal and connective tissue disorders | 2 of 52 |
| Blister | Skin and subcutaneous tissue disorders | 2 of 52 |
| Psoriasis | Skin and subcutaneous tissue disorders | 2 of 52 |
| Rash generalized | Skin and subcutaneous tissue disorders | 2 of 52 |
| Anemia | Blood and lymphatic system disorders | 1 of 52 |
| Myocardial infarction | Cardiac disorders | 1 of 52 |
| Vertigo | Ear and labyrinth disorders | 1 of 52 |
| Abdominal pain | Gastrointestinal disorders | 1 of 52 |
| Ascites | Gastrointestinal disorders | 1 of 52 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Moderate or Severe Psoriasis |
|---|---|---|
| Influenza like illness | General disorders | 5 of 52 |
Serious events with the highest arm-level rate: neck pain (3.8%), psoriatic arthropathy (3.8%), blister (3.8%), psoriasis (3.8%), rash generalized (3.8%).
The safety record lists 16 serious adverse events among 52 at risk and 5 other adverse events among 52 at risk for the moderate or severe psoriasis group. These are recorded event counts, not a comparative estimate of risk between randomized treatment groups. The registry does not report deaths in this entry. Whether these counts represent participants with at least one event or event occurrences should be interpreted in light of the registry’s event-reporting conventions; further detail is not reported in the registry record.
The serious adverse-event terms with the highest listed percentages are neck pain, psoriatic arthropathy, blister, psoriasis, and rash generalized, each at 3.8%; anemia is listed at 1.9%. These percentages describe the entries in the registry and do not establish that an event was caused by adalimumab. The record does not provide event timing, severity grades beyond the serious-event classification, exposure duration, or a treatment attribution assessment.
In general, safety counts require context about who was observed, for how long, and how events were defined and collected. Here, the listed group is not a randomized control comparison, so the counts do not support a relative safety conclusion. They should be read separately from the unreported primary PsA outcome results.
12. What the Result Does, and Does Not, Mean
The registry record establishes what the investigators intended to measure: the percentage of eligible participants meeting a defined PsA case definition at baseline, visit 3 (month 6), and visit 4 (month 12). It also documents an adalimumab-treated group of participants with moderate or severe plaque psoriasis and lists related secondary outcomes. These registry entries describe the scope of the study, not its numerical findings.
The primary outcome results are not reported in the registry record. Consequently, the record cannot establish the observed percentage meeting the PsA definition, whether the measure changed across visits, or how precise any estimate would be. A missing result should not be interpreted as a zero result, as evidence that participants did not develop PsA, or as evidence that the outcome was unchanged.
The design information also limits what could be concluded about treatment effects. The record says allocation is not stated and that this was not a randomized comparison. In general, observations over time within a treated group can describe what happened during follow-up, but cannot by themselves identify what would have happened to comparable participants under a different treatment or no treatment. The record does not provide a control contrast or statistical adjustment that would resolve this limitation.
The listed safety entries give some information about adverse events recorded in the group, but they do not show whether treatment caused those events or how event rates compare with another group. The listed secondary outcome names likewise do not establish efficacy or safety findings; numerical results are not reported in the registry record.
In practical statistical terms, the record is useful for understanding the endpoint definition, planned assessments, and limits of the design. It is insufficient for estimating PsA prevalence or incidence from the primary outcome, for judging change over time, or for drawing a causal conclusion about adalimumab. Those conclusions require numerical results and supporting analysis details that are not reported in the registry record.
13. Why This Trial Matters Statistically
This study is statistically notable because it links a clinical case definition to repeated assessment of joint-related disease in a population described as having moderate or severe psoriasis. The primary outcome does not rely on symptoms alone: it permits a rheumatologist’s diagnosis or specified joint findings combined with a CASPAR threshold. This makes the operational definition important to the interpretation of any event percentage.
The record also highlights a common distinction between a study’s stated purpose and the information needed to evaluate its results. It names prevalence and incidence in the title and lists both an endpoint at visits and a secondary time-to-first-occurrence measure. Those are related but different statistical summaries. A percentage at an assessment describes the proportion meeting a definition at that time, while time to first occurrence concerns when an event is first observed. The registry record does not provide the numerical estimates or analytic details needed to compare those summaries.
Another important feature is the absence of a randomized comparison. Without a like-for-like control group, observed changes during treatment cannot isolate treatment effects from other factors. This design constraint is especially relevant when the study’s stated purpose includes evaluating efficacy and safety. The record’s caution about nonrandomized allocation should therefore guide interpretation of any group-level observations.
Finally, the record illustrates why denominators and missing-data descriptions matter. The primary outcome population requires completion of specified rheumatology visits and available information, but its size and missingness details are not reported. A percentage without a clear denominator and uncertainty estimate can be difficult to assess. Since numerical results are not reported, the most defensible statistical reading concerns what was planned and defined, rather than what the study found.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The main trial-specific limitation in the registry record is that numerical results for the primary outcome are not reported. The record does not give the event percentage at baseline, visit 3, or visit 4, nor the event counts, denominators, or confidence intervals. Thus neither the level of PsA occurrence nor its precision can be evaluated from the primary outcome entry.
The primary population is defined by completion of visits 3 and 4 and availability of information, but the number of participants satisfying that definition is not reported. The record also does not report counts or reasons for missing assessments, or how missing data were handled. This limits assessment of possible selection and attrition effects when interpreting the intended percentage.
The study is not described as a randomized comparison, allocation is not stated, and the registry cautions against treating arms as like-for-like controls. This precludes a straightforward randomized treatment contrast. The record does not provide sufficient analysis detail to assess whether measured confounding was addressed, and the statistical plan is not reported.
The case definition combines clinical judgment with joint and CASPAR criteria. The record does not report how assessments were standardized across visits or whether case decisions were independently reviewed. That does not establish that ascertainment was inconsistent; it means the relevant procedures are not reported in the registry record.
Finally, the record lists secondary outcome measures but does not report their numerical results, analysis methods, or multiplicity handling. Details of eligibility criteria, treatment duration, exposure, interim analyses, and the study’s own sample-size justification are also not reported in the registry record. These limits restrict both the clinical interpretation and the statistical appraisal of the study.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Prevalence and Incidence of Articular Symptoms and Signs Related to Psoriatic Arthritis in Patients With Psoriasis Severe or Moderate With Adalimumab Treatment — NCT01316224.
- Registry record last updated 2015-05-12; status last verified 2015-04.
- Results first posted 2015-05-12.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
NCT01316224 is a completed study of adalimumab treatment in participants with moderate or severe plaque psoriasis, with an enrollment of 52. Its stated purpose was to describe the profile of participants in Colombia and evaluate efficacy and safety. The primary endpoint is the percentage meeting a defined PsA case definition at baseline, visit 3 (month 6), and visit 4 (month 12).
The registry defines the endpoint population as participants who completed visits 3 and 4 to the rheumatologist and had information available. Numerical primary and secondary outcome results are not reported in the registry record. Allocation is not stated, and the registry cautions that this is not a randomized, like-for-like comparison. Serious and other adverse-event counts and selected serious-event terms are listed, but they do not provide a comparative safety estimate. Missing-data procedures, statistical methods, multiplicity handling, and the study’s statistical plan are not reported in the registry record.